In the past week, we’ve seen LED Christmas trees of digital logic and a great freeform circuit version. Unlike these other builds [Danilo]’s LED tree uses a piece of protoboard masterfully cut into the shape of a Christmas tree. There’s no PCB for this build; just a lot of bare wires and a lot of patience.

Because [Danilo]’s tree makes use of the PWM pins on his Arduino, it was possible to connect his tree to the Arduino with a few 90 degree headers. This provides a great base for his tree and makes it possible to build a professional-looking enclosure for his project.

while i find this annoying i must admit i made my own arduino Christmas tree when i was starting out.
it was a grid of 5*5 leds on lengths of green cat5 pairs, twisted together to make the trunk and spread out to make branches.
i meant to make a stand alone out of it and give it away but i didn’t have a crystal and i couldn’t figure out how to use internal oscillator so it got scrapped.

feels like ages ago.
while it is a common and decent way to learn, i wouldn’t want it on hackaday then, and certainly not now

I do not understand this “Arduino” device. But I commend you on your perseverance in solving the problem with such a complicated tool.

In my laboratory, I invented a similar contrivance that uses fewer components. A piece of phenolic insulating board was cut into the shape of a tree. Placed upon it are a number of gas discharge tubes (type NE-2 etc.) with various gases within to provide the colors (e.g. orange, blue, green, and such). Ten megohm carbon composition resistors and 0.1uF condensers were connected as relaxation oscillators to provide a pleasant blinking rate.

Power consumption is exceptionally low. It has operated for months on a 90v B battery that was already depleted so as to be of no further use in a radio.